ZOOLOGY. MOLLUSCA. 201 



Helix kypolepta. Shuttleworth, Diagnosen neuer Mollusken, 

 no. 6, from the Bern. Mittheil., March, 1854, p. 129. 



The group Micropliysa, in which I have placed this shell, has 

 been a stumbling block to most of the authors who have rec- 

 ognized it. It consists of small, umbilicated, thin, hyaline 

 shells, with sharp lip to the lunar-oval aperture, convex whorls 

 and impressed sutures. There is little in all this to separate it 

 from certain forms of Zonites (Z. minusculus, for example). 

 But the Zonites have narrow aculeate marginal teeth to the 

 radula, while these shells, typified by //. Boothiana Pfr., have 

 the dentition of Patula. The marginal teeth are low and wide, 

 with several denticles. 





